This is a Data Management and Biostatistics Core Facility proposal in response to the RA entitled Centers for Children's Environmental Health and Disease Prevention Research (RFA ES-94-004), which is aimed at addressing treatment questions for hazardous environmental exposures and children's respiratory disease. The purpose of the work outlined herein is to collaborate in the planning of the epidemiologic and interventional studies; to coordinate activities related to data collection, management, and analysis for the Center for Childhood Asthma in the Urban Environment (CCAUE) to be created via the RFA; and to provide expertise with regard to the design and conduct of the proposed epidemiologic study and clinical trial. The proposed activities will be housed in the Center for Clinical Trials (CCT), located in the Johns Hopkins School of Hygiene and Public Health on the East Baltimore Campus of the Johns Hopkins University. The CCT, and its associated activities, involves a facility of 27 and a combined facility and staff of 60+. It is a group committed to the science of trails and to the art of creating and maintaining collaborative structures cutting across disciplinary lines. CCT computing hardware and software are state of the art. The CCT is experienced as the Coordinating Center for 16 multi-center clinical trials, since its inception as an entity in 1981. The senior personnel are all trained and experienced in research design and analysis, and are collaborative investigators. The CCT will bring to bear its corporate expertise in its specific duties regarding collaborative protocol development, consent process development, sample size calculations, validation of measurement instruments, database design, forms development and piloting, personnel training and certification, performance and treatment effects monitoring, specimen tracking, maintenance of the database, quality assurance methods, statistical analysis, paper-writing activities, research group communications, and organization issues.